Circuit Design Based - Computer Science - Lecture Slides, Slides of Computer Science

Download Circuit Design Based - Computer Science - Lecture Slides and more Slides Computer Science in PDF only on Docsity!

VHDL

Main topics:

• Circuit design based on VHDL
• VHDL basics
• Advanced VHDL language structures
• Circuit examples

Shortly About the VHDL

• VHDL is an acronym of VHSIC Hardware Description Language
• VHSIC is an acronym of Very High Speed Integrated Circuits
• A Formal Language for Specifying the Behavior and Structure of a Digital Circuit
• Allows Top-Down Design

VHDL for Simulation & Synthesis

Test Vector Generator

A Series of Refined Models

Executable Specification

Test Vectors

Results, = Errors

Final Chip Model

VHDL for Simulation & Synthesis

VHDL requirements for Simulation

• Creation of test benches =>
  • File I/O
  • Detection of errors (function & timing)
  • Multiple simultaneous models
  • Combination of low & high level models (for efficiency)

VHDL for Simulation & Synthesis

Requirements for VHDL Synthesis Tools

• Pre- & post synthesis behavior should be identical
• Synthesis should be efficient =>
  • Requires interaction with place & route tools
  • Logic Synthesis
  • FSM Synthesis
  • Area & Timing Optimization

New possibilities

• VHDL frees the designer from having to use von Neumann structures - (Neumann János = John von Neumann)
• It allows him to work with real concurrency instead of sequential machines
• This opens up completely new possibilities for the designer

Origin of the VHDL

• VHDL originated in the early 1980s
  • The American Department of Defense initiated the development of VHDL in the early 1980s - because the US military needed a standardized method of describing electronic systems
• VHDL was standardized in 1987 by the IEEE
• It is now accepted as one of the most important standard languages for - specifying - verifying Docsity.com

Standardization 1

• IEEE standard specification language (IEEE 1076-1993) for describing digital hardware used by industry worldwide
• VHDL enables hardware modeling from the gate level to the system level
• All the major tool manufacturers now support the VHDL standard
• VHDL is now a standardized language, with the advantage that it is easy to move VHDLDocsity.com

Standardization 3

• It was the American Department of Defense which initiated the development of VHDL in the early 1980s because the US military needed a standardized method of describing electronic systems
• VHDL was standardized in 1987 by the IEEE
  • IEEE Std-1076-
• ANSI Standard in 1988
• Added Support for RTL Design
  • VITAL: VHDL Initiative Towards ASIC Library Docsity.com

Standardization 4

• numeric_std/bit: IEEE-1076.
• VITAL: IEEE-1076.
• 1999: IEEE-1076.1 (VHDL-AMS )
• 2000:
• IEEE-1076-
• IEEE-1076.1-2000 (VITAL-2000, SDF 4.0)
• Added mixed-signal support to VHDL in 2001 ->

Usage

• High-tech companies
  • Texas Instruments, Intel use VHDL
  • most European companies use VHDL
• Universities
• VHDL groups to support new users

IEEE

• IEEE is the Institute of Electrical and Electronics Engineers
• The reference manual is called IEEE VHDL Language Reference Manual Draft Standard version 1076/B
• It was ratified in December 1987 as IEEE 1076-
• Important:
  • the VHDL is standardized for system specification Docsity.com

Analog world

• VHDL has not yet been standardized for analog electronics
• Standardization is in progress on VHDL with an analog extension (AHDL) to allow analog systems to be described as well
• This new standard will be based wholly on the VHDL standard and will have a number of additions for describing analog functions

VHDL-Related Newsgroups

• comp.arch.fpga
• comp.lang.vhdl
• comp.cad.synthesis